1 /*
2 * Copyright (C) 2003-2008 Takahiro Hirofuchi
3 *
4 * This is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
17 * USA.
18 */
19
20 #include "usbip_common.h"
21 #include <linux/kthread.h>
22
event_handler(struct usbip_device * ud)23 static int event_handler(struct usbip_device *ud)
24 {
25 usbip_dbg_eh("enter\n");
26
27 /*
28 * Events are handled by only this thread.
29 */
30 while (usbip_event_happened(ud)) {
31 usbip_dbg_eh("pending event %lx\n", ud->event);
32
33 /*
34 * NOTE: shutdown must come first.
35 * Shutdown the device.
36 */
37 if (ud->event & USBIP_EH_SHUTDOWN) {
38 ud->eh_ops.shutdown(ud);
39
40 ud->event &= ~USBIP_EH_SHUTDOWN;
41 }
42
43 /* Reset the device. */
44 if (ud->event & USBIP_EH_RESET) {
45 ud->eh_ops.reset(ud);
46
47 ud->event &= ~USBIP_EH_RESET;
48 }
49
50 /* Mark the device as unusable. */
51 if (ud->event & USBIP_EH_UNUSABLE) {
52 ud->eh_ops.unusable(ud);
53
54 ud->event &= ~USBIP_EH_UNUSABLE;
55 }
56
57 /* Stop the error handler. */
58 if (ud->event & USBIP_EH_BYE)
59 return -1;
60 }
61
62 return 0;
63 }
64
event_handler_loop(void * data)65 static int event_handler_loop(void *data)
66 {
67 struct usbip_device *ud = data;
68
69 while (!kthread_should_stop()) {
70 wait_event_interruptible(ud->eh_waitq,
71 usbip_event_happened(ud) ||
72 kthread_should_stop());
73 usbip_dbg_eh("wakeup\n");
74
75 if (event_handler(ud) < 0)
76 break;
77 }
78 return 0;
79 }
80
usbip_start_eh(struct usbip_device * ud)81 int usbip_start_eh(struct usbip_device *ud)
82 {
83 init_waitqueue_head(&ud->eh_waitq);
84 ud->event = 0;
85
86 ud->eh = kthread_run(event_handler_loop, ud, "usbip_eh");
87 if (IS_ERR(ud->eh)) {
88 printk(KERN_WARNING
89 "Unable to start control thread\n");
90 return PTR_ERR(ud->eh);
91 }
92 return 0;
93 }
94 EXPORT_SYMBOL_GPL(usbip_start_eh);
95
usbip_stop_eh(struct usbip_device * ud)96 void usbip_stop_eh(struct usbip_device *ud)
97 {
98 if (ud->eh == current)
99 return; /* do not wait for myself */
100
101 kthread_stop(ud->eh);
102 usbip_dbg_eh("usbip_eh has finished\n");
103 }
104 EXPORT_SYMBOL_GPL(usbip_stop_eh);
105
usbip_event_add(struct usbip_device * ud,unsigned long event)106 void usbip_event_add(struct usbip_device *ud, unsigned long event)
107 {
108 spin_lock(&ud->lock);
109
110 ud->event |= event;
111
112 wake_up(&ud->eh_waitq);
113
114 spin_unlock(&ud->lock);
115 }
116 EXPORT_SYMBOL_GPL(usbip_event_add);
117
usbip_event_happened(struct usbip_device * ud)118 int usbip_event_happened(struct usbip_device *ud)
119 {
120 int happened = 0;
121
122 spin_lock(&ud->lock);
123
124 if (ud->event != 0)
125 happened = 1;
126
127 spin_unlock(&ud->lock);
128
129 return happened;
130 }
131 EXPORT_SYMBOL_GPL(usbip_event_happened);
132